Method of making crankcases



Aug. 14, 1945.d T, I FAWICK 2,382,303

METHOD OF MAKING CRANK-CASES' Filed April ze, "1944 s sheets-sheet `1 /0 l f f /A Z5 /0 /7 /q /5 /7 /Oa /4 l /6 /6 2/ f n 202 /a K l f l Il/ lob [5 /4 V /4 `/2 i y l? /z y j 2g /OQ /7 y /7 INVENToR. THQ/m45 L FAW/ck Arm/@Nw Aug. 14, .1945. 11..., FAWICK 2,382,303

METHOD OF MAKING CRANK-CA$ES Filed April 26, 1944 3 Sheets-Sheet 2 INVENTOR. 7710/14/16 Lw/6K I Aug.14,1945. f T..| FAwlCK 2,382,303

METHOD v0F MAKING cRANK-cAsE's Filed April 26,v 1944 A s sheets-sheet 5 r Y N l, f/ fa .8 l/x my' d g l /ly a INVENTR. 771047,45 L, FAW/CK Patented Aug. 14, 1945 y rsaemsvV L l f METHoDl F MAKING'IQRANKCASES g Thomas L. Fawick, Akron,-` I

Application April as, 1944, serial Nasgaia Y 3 Claims.

This invention relates to methods for making crank `cases for internal combustion engines. It is of especial value in quantity production of crank cases for the motors ofV air-craft, wherein lightness, strength and accuracy of dimensions are oflutmost importance. Some of the subject matter disclosed in this application is described and claimed in my co-pending application Ser. No. 428.851, led January 30, 1942, of which this application is a continuation-impart.

Because of the above mentioned requisites, and because the several portions of the crank case have to be thin but extensive in several directions, an inordinate amount of machining of large aluminum or steel'forgings has been required in the procedure that has been for a long time, and still is,` the general practice, in spite Iof the present urgent need for saving time, labor and shipping costs and for reducing waste of materials in machining operations.

apertured, disc-like, conical, bearing-support members I I, I I, which havemounted therein cen-` trallyapertured, flanged, annular, seating mem- The chief objectsjof this invention are economy of time and of laborfavoidance of the high cost of shipping large and heavy parts from city to city for the forging and machining operations, the reduction of the amount of machining waste, and the provision of accuracy, lightness and strength in the` finished product.

Of the accompanying drawings:

Fig. 1 is a fragmentary axial section of a crank case, for asingle bank of cylinders, made in accordance with my invention in its preferred form.

Fig. 2is a fragmentary axial section of a crank case, lfor two banks of cylinderamade in accordance with my invention in its preferred form.

Fig. 3 is a fragmentary-section, on a larger` scale,` of parts shown in Figs. 1 and 2.

Fig. 4 is a fragmentary perspective view of a piece of rolled metal as it appears at an early "stage in the preferred procedure for forming a` part of the crank case.

Fig. 5 is a fragmentary perspective view of th'e same piece `as it appears at a later stage.

Fig. 6 is a fragmentary perspective view shoW- ing the same piece at a still later stage.

Fig; 7 is a sectional view of forging dies, with the work therein, illustrating the preferred `proi III bers I2, I2 for the crank-shaft bearings, the mem-` bers I0 being adapted to be `secured asby bolts I 0a, I Ila to a reduction gear and propeller-bearing housing ,Illb and to an engine support ID, respectively.` i i I i Heretofore the crank case, having portions cor` responding to the four members I 0., I0 and II, `I I; have been made-integral withl each other, by ma` chining of a single metal forging, and it is manifest from contemplation ofthe final shape of ,f such` a member that the machining jobisexpensive, being wasteful of`time,'labor, material, and shipping costs. l l l #In the practice of my invention each of the members Ill is hot-rolled longitudinally to ap-uk proximately its iinal channeled cross-sectional formjin straight lengthsyas illustrated at I0X in Fig. 4r4 and Illy` in Fig. 5 butwith allowance for the relativelysnall amount of machiningrequired. The longitudinal hot-rolling provides a longitudi- `nal lgrain in th'e metal which in the na1 product torch, with` 'allowance for a relatively Vsmall i amount of machining, to provide holes for thel mounting ofthe engine cylinders when two of the members `I0.are secured together as shown,` by'bolts' I5, `I5 extending through holes boredin lugs i6, `l'iwhich are the `remaining portions,

` after" the hole cutting operationi of annular inter# nal vflanges which are formedion the members I II` in-the rolling operations."

Before the members I0 are thus bolted together, h'owevenlthey are sized in suitable dies, and each hasmounted'in iton'e of the bearing-support disc-` like member-sil I. v if Each of the members II is made by forging a billet,lshown in'dottedlines I IW and I Ixin Fig.`7,' which` preferably has its greatest dimension in the direction of the blows ofthe hammer, for Iproviding a pronounced radial grain in the metal of the resulting blank I Iy for the sake of strength.

Th'e production of such radial grain can be visualized from the fact that as the billet is forged it changes from the shape I Ix to progressively more flattened shapes such as the shape IIY and that the vertical dimension a-b along its surface in IIW becomes the greater dimension a'-c,b in

' IIXs suchincreases being greater in percentage than the simultaneous increases of circumference.

After they are hammered approximately :to size and shapethemembers I I are brought,as;shown at I Iz in Fig. 8, to a closer approximation oi' their `na1 conical form by pressing them in dies, after which they are centrally bored `for reception of` v the bearing seats I2 and are machined at their outer peripheries to t within the respective members I and against respective annular shoulders I 1, II formed on the inner faces of the members I0. The central holes can be roughly formed by the punching out of a disc Il", Fig.. 8, in the kdie-shaping operation.

' Because the; outer diameter of." each member'llt isgreater than the inner` diameter of the flange oi'which the lugs Nifarez residual parts, each meme' inserted: im themember I0, from the larger endV or the latter; in lugs' I-f.:

The members II, being mounted in theresp'ec tive members Hl; are` thenI secured inplacaprefera-by by welding, atY 119,1 after which the assemblies' comprising the members;` I0, II' and t2' arew bolted' to eachother, the cylinder` holes providing access for the bolting operation.

Holes Ev forthevalve push-rods and apertured spite of the presenceA of' the il'ats forv the mounting ofthe pushrod guides' stantially to that shown in Fig. 1, except that, for.y twol banks of cylinders, the radially outer portion offthecase comprisestwo members I0, I0, corresponding to the members I-il of Fig. 1, and betweenv them a; member Ilfll.y suitably formed, by corresponding procedure, tomate withv the members Ill' embracing. it.

Each-y of' they members', I0' ofV Fig. 2vhasmountedV in it a conical, disc-like, bearing-support'nember Hf, `made andmounted inthesame way as in Fig.

l, `and at its middle the member IIB has 'somewhat similar member, I'I I-, mounted'in itin thesameway except. thatthe member I'I I is uted in its. radially outer' portion, with? theflutes, I'IIa,

IIfla, ofincreasing'depth toward its outer peripl'1. ery, andv is heldin placel by welding'shown lat Iss, ISH', on both sides of its outer margin, the iluting thus providing a high degree of strength. Asthe sinuouswelds ISa provide' strong anchorage of the member III to the membery III] a sinuous shoulder on the latter isnot required'and consequently the member I I0 can be'economically formed. by substantially the same rolling' operar tions andfurther procedure thatv are above-described as to the members I0 of Fig'. 1.5 i l' As the member I II fits against 'ai cylindrical innerface of the member IiI Il which isof substantial width and as the latters lugs I6, |621, are a considerable distance apart, the member III can be mounted in the member IIU without being formed with notches in its outer margin.

The invention provides the advantages that are set out in the above statement of objects and other modifications are possible Without sacrice of all such advantages and without departure from the scope of the appended claims.

I claim: l l

1. A method of making a crank-case for an internal combustion engine which comprises applying rolling pressure by longitudinal progression to respective masses of metal and thereby producing two longitudinally grained metal strips, bendingv each to ring form and joining its ends by welding to provide two annular shell members having circumferential grain, producing two ra- ,diallygrained bearing support members by forging a billet, for each, initially having a relatively large dimensionin theY` direction 'ofvthe hammer blows, mounting `the bearing-support members ,respectivelyin and securing themv respectively to the inner surfaces of the shell members, and securing an annular marginfof one of the shell mem-bers'to anV annulary margin of theother.

' 2. 'A method ormaking a crank-case for an interna-l combustiony enginev which comprises applying rolling pressure by longitudinal progressiony to respective masses: of-*metal and thereby producing two longitudinallygrained metal strips, bending'ea'ch to ring form and joining its ends by weldingy to provide two annular shell members having circumferential grain, producing two radiall'y grained bearing-support members by forging a billet, for each, initially having a relatively large dimension' inthe direction of the hammer blows, mounting the bearing-support members respectively in and securing th'em respectively to the inner surfaces of the-shell'members, and securing an annular margin ofone of the shell members to an annular marginfof the other; the method including the step off forming respective circumferential series of registerable notches in v the said margins of the two shell members before the two said margins are secured together, so that the notches register in'pairs to form a circumferential seriesof' cylinder holes in the resulting assembly.

3'. A method of' making'a crank-case for an internal combustion^'engine which comprises applying rolling pressure bylongitudinalprogression to respective masses` of' metaland thereby producing two longitudinally grained metal's'tri'ps, bending each to ring form and joining its endsby welding to provide two 'annular' shell members having circumferential grain, producing two radially grained bearing-support' members-by forginga'billet, for each, initially having a relatively large dimension in the direction of rthe hammer blows, mounting the bearing-support members f respectively in and securing them respectively to the inner surfaces ofthe shellfmembers, and securing an annular margin of one of the shell membersto an annular marginof the-other, each of the shell members being'formed', in the rolling step, with an internal marginal' attachment fiange and said flange being bent to ring form asian integral unit' with the rest ci the shell member.

THOMAS L. FAW'ICKL 

